Description Polarizing Filter - 1.25" (BPPOL125) and 2" (BPPOL2) A polarizing filter is an excellent filter choice for lunar viewing. It provides variable neutral density (it darkens or lightens) as it is rotated, accomodating the different lunar stages. This filter is a single stage polarizing filter and must be used with a diagonal mirror, such as our MaxBright Diagonal (PMDMAX), to achieve the polarizing affect. This polarizer can similarly be used with a Herschel Prism (BPHERP) for solar viewing, but must always be used in addition to the ND3.0 filter (the ND3.0 filter must always remain in the Herschel Prism for viewing safety). When either lunar or solar viewing, the filter can be screwed onto the barrel of a 2" eyepiece or onto our 1.25" Eyepiece Adapter (ADA125). Note that in the case of our ADA125, you may need to add our 2" Barrel Extension (A3703) to accommodate 1.25" eyepieces with extra long barrels.
